Fuel Leak Baffling Me...

[GregAmy]

So I bought a '74 914 "driver". Rough condition, sat around for a while under a cover. I got it running, filled it up with fuel and then noticed a bad fuel leak. Turns out it was leaking from the electrical connector on the fuel pump up front. I swapped that out and it was fine, no more leaks.

Then, a week later, I drove it several times over a weekend and parked it. I came back into the garage the next day and found it filled with a bad fuel smell. Saw fuel creeping out of the underside of the 914. However, this was not clear fuel, it was an oily, watery mix of fuel and whatever:



It's dripping off the bottom of the car, under the master cylidner toward the left side. It's mostly dripping off the area where a "ring" is welded onto the car, just to the right of the master cylinder. Could not figure out what it was, but after a couple days and a half gallon later, it stopped. I thought maybe it was residual fuel/water under the cowl, so I poured in a gallon or so of water into the cowl and behind the tank, and all that came out on the driveway was water...seemed fine to me.

Then, this past weekend, I drove the car around again and...you guessed it...I found a whole bunch of oily, watery fuel under the car:



I have NO idea where this is coming from. The only clue is that I added fuel to the car both times, but I did not fill it up; I added to about half a tank both times. Previous owner said he had removed the tank to check for a fuel leak (he'd not seen it dripping from the fuel pump) and said he'd "pressure tested" the fuel tank with a bicycle pump, found no leaks. The hoses coming off the bottom of the tank and all around the fuel pump are all new, and that side of the car underneath is bone dry.

Now, I accept I may have a fuel tank leak somewhere, but that would not explain the oil and water in the mix.

I'm stumped, ideas appreciated.

- Greg

[Dave at Pelican Parts]

My only guess is that the fuel leak is running into standing water somewhere, and carrying the water with it.

Time to pull off the "gravel guard" under the steering rack and check for leaks and water. You can look through the ~6" hole from the steering rack compartment to the fuel tank compartment. Hopefully you'll see and/or feel something.

How do you know the fuel lines are new? The PO told you, or you verified for yourself?

I have the feeling you're going to be pulling the tank out of this car for inspection, if nothing else. The good news is that it's not hard to do, though the tank is difficult for one person to pick up and maneuver.

--DD

[GregAmy]

Originally Posted by Dave at Pelican Parts

Time to pull off the "gravel guard" under the steering rack and check for leaks and water.

Already missing, unfortunately...this is a pretty rough "driver".

How do you know the fuel lines are new? The PO told you, or you verified for yourself?

When I picked up the car I dropped it off at a local "914 guy" for inspection/estimates and he replaced the rubber and steel fuel lines that go to the back. I also verified visually that the rubber lines were all good up to the tank fittings on the right side when I had the car on the lift replacing the fuel pump/filter assembly (replaced it with a two-fitting pump).

Also, recall the leak is coming from under the master cylinder on the left. All the lines I saw were on the right side, and it's dry over there at the hole where the rubber lines go up to the tank.

I have the feeling you're going to be pulling the tank out of this car...

Me too, and I'm trying to avoid it. Just looks like a PITA...I can remove the lines from the pump/filter assembly and leave them attached to the pump; is there anything else holding in the tank except that strap across the top? What are my replacement options?

But if someone has another idea before I go that route, I'm all ears.

- GA

[Dave at Pelican Parts]

If the charcoal canister is on top of the gas tank, you'll want to remove it. I recall removing the expansion tank from the top of the gas tank and the filler as well. (Don't drop any of the bolts into the tank!)

There are two rubber blocks at the left and right sides of the tank; they fit onto the seam around the tank. That and the strap are basically it.

There are three felt pads under the tank, and they like to hold water and can promote rust where the tank sits on them. One of them could be the source, possibly.

--DD

[Racer Chris]

Originally Posted by GregAmy

When I picked up the car I dropped it off at a local "914 guy" for inspection/estimates and he replaced the rubber and steel fuel lines that go to the back.

When a fuel tank has a couple gallons or more in it, Ed doesn't like to remove it unless we have a specific reason.
He's gotten quite good at installing stainless lines and connecting hoses just using the access hole.

A fuel tank leak seems likely...except for the water content...and that fuel on the floor looks rather old.
We probably would have found the source if the car was road legal while it was here.
A real mystery so far. I'm very interested in seeing the outcome of this one.

[John Rogers]

The water mixture is the strange part. There are several places on the car that are closed enough to hold water and then get shaken loose such as the side box sections, tunnel, heater system, doors, firewall and some others. If it were me, I would clean the floor very well and then drive it a short bit and come back into the garage and park it. Then I would lay down with a good strong light and watch for the first drip or two and that would tell me where it is coming from. Unfortunately this means "watching the kettle boil" and may take an hour of so but eventually there will be a drip or two. A good pillow might help, good luck.

[GregAmy]

Ok, found the fuel leak.

Removing the tank wasn't terrible. Other than getting fuel running down into my armpits, it was a pretty straightforward job (removing the "bonnet" was a plus.) Using some plugs, my good ole lungs, and a spray bottle of Windex, I quickly found it.

There is a rusty area on the underside of the tank toward the driver's side, on the horizontal bit that rolls backward over the body. The tank was rubbing on the body there, the paint o the tank was rubbed away, and the tank rusted (body actually looks fine). The hole is very small, but enough so that it was leaking whenever the fuel level was above just that bottom part. The previous owner said he checked it with a bicycle pump; I tried pressurizing it and holding everything closed for five minutes and it still held pressure (I was not using a gauge). Had I not used the spray Windex I would have never found it...

This doesn't explain the water, and it doesn't explain the oil, but I'll fix this leak and see what comes of it...

So I'm debating whether I want to use a Permatex patch kit or see if there's a local pro that can solder this for a reasonable price. Anyone used the Permatex stuff (or equivalent?) I'm also going to glue a thin rubber pad there where the tank sits on the body so they don't rub together again.

BTW, how do those rubber side parts for the tank fit? Do I slide them in place after putting the tank in? I was expecting them to be bolted in or something.

Thanks for the help!

- GA

[TheCabinetmaker]

i'd replace teh tank, could be many thin spots where it rubbed, I could live with a patch it the car was never parked inside, but only at a temporary repair. gas tanks are not too expensive.

the next question is why did it rub?????

there should be the two black rubber tank holders, one on each side of the tank, and there should be several white felt pads, about 1/4 inch thick or so. i recall two felt pads at rear of tank near the top, and at least one more felt pad on the upper step of the bottom of the tank. the pads were roughly about 3 inches by 5 inches in size.

make sure also you have no water leaks nor brake fluid leaks, as either can soak into the flt pads, and cause rust.

since the gas tank is out, now is time to lube the wiper shafts (and test that they seal out water), and besure when re-installing the shafts that the shaft bushing protrudes out of the body past the top of the well that they sit in, else water will stand in that well and run into the shaft bushing and get inso the trunk. by using the double nuts the length the shaft sticks out can be adjusted,

also now is time to service the fresh air blower, you cant get it out with the gas tank installed. clean the blower, lube the bearings, and besure to install an aluminum window screen painted black over the blower opening, under the cowl grill. this will prevent small debries from getting into the blower. besure to clean out the blowers drain tubes. and test for water leaks at the cowl once the blower is re-installed, before the gas tank goes back in. the rubber seal on the top of the blower to the underside of the cowl is critical to keep water out of the front. leaks here will soak the gas tank felt pads, and can even cause drips on the cockpit floor.

besure to replace the rubber hoses under the tank, use SAE 30R9 hose or better, do not use 30R7 as todays new government mandated oxygebnated fuels which not only cost more, and deliver worse milage, will also eat up the older style fuel hoses. what was safe to use ten years ago with the old gas, is not so safe with todays crap gas. the 30R9 hose is lined with a teflon like material that resists the damaging government mandated gasoline. thanks to the corn industry and thier lobbiests for that crap gas!

[Racer Chris]

Greg,
I would tig weld a patch if its the only bad spot on the tank.
Making it safe for welding is the hardest part.
In the northeast I have no idea where you'll find an inexpensive good tank to replace that one.
I have some felt pads if you need. Some people use pieces of carpet.
The rubber blocks are moved into position just before the tank drops into place. Its not difficult with two people.

[Dave at Pelican Parts]

The rubber blocks (the "tank holders") sit on the seam of the tank up at the corners. You put those on before you lower the tank back into place, and then fuss with their exact position once the tank is in.

--DD

[GregAmy]

I still have the two rubber parts, but there was no felt anywhere in there. Where does that go?

Looks like there was some welding down there in the cockpit pedal area. Since I have access to the other side I'll rust-proof and paint that side to stop rust.

I've got access to a TIG, but I don't trust myself or my buddies to do that. If I can't find an experienced tank repair place I'll have to go with the resin/plastic patching option.

CabinetMaker, thanks for the other tips, I'll check into those while I've got it out.

- Greg

[esses62]

Hey Greg,
I think we spoke once before. I have an extra tank if you want it free of charge. I think it's from a 75 but I should work for you. Shipping would be expensive but if you want to pick it up its yours Just send me a PM

Scott

[Dave at Pelican Parts]

The felt pads are located where the rub points would be. Some digging on Goggle Images has turned up some photos.


Here is one that shows the most obvious location, and the least obvious one:





Here is one that shows where all four pads would be. Look on the front wall of the tank compartment (right-center in this photo); there is a piece that curves inward. There are two rough spots with paint missing on that curved bit, those are the locations for the other two pads.




--DD

[GregAmy]

Originally Posted by esses62

I have an extra tank if you want it free of charge.

Scott, sincere thanks. PM on the way for an estimate of shipping.

Originally Posted by Dave at Pelican Parts

The felt pads are located where the rub points would be.

Yup, that makes sense. My rust/rub/hole area is the one in that top photo toward the driver's side that is framed within that curved hose. In the bottom photo that lower "paint missing" areas you describe is where my tank rubbed and caused the hole. Strange those are missing but "ah well"...

In looking deeper at it, I'm thinking the oil is coming from what Chris described to me via private email, the fuel cleaning off the car. And I'm guessing maybe the water could be from hanging around outside? I dunno, one prob at a time...

- Greg

[Racer Chris]

Originally Posted by GregAmy

I've got access to a TIG, but I don't trust myself or my buddies to do that. If I can't find an experienced tank repair place I'll have to go with the resin/plastic patching option.

We'll do it if you want.
I've repaired many automobile gas tanks in the past 25 years - haven't blown up yet.

[TheCabinetmaker]

Note on the yellow car in daves posted photo, the driver side pad is missing and the paint is worn where the pad should have been.

that oil you find under your car with the gasoline leak could be the result of rubberized undercoating being soaked in gasoline. Some tar based coatings will disolve in gasoline and have the appearnace of an oil and gasoline mix. Gasoline spilled on the cockpit floor will also disolve the sound deadening tar matts that the facoty glued to the floor, this too will give the appearance of oil and gasoline. if gasoline got into the tunnel, it has a direct path to the cockpit floor, the gasoline will seep under the tar matts, dissolve a bit of the matts, the liquid now appearing as oil, the liquid then drips on the garage floor thru drain holes.

I sold a sare gas tank a few years back for $75 free is a good deal if the shipping is not to high.

some radiator shops can repair gas tanks with welding or brazing, so you might ask them if you have a local one.

[GregAmy]

Originally Posted by Racer Chris

We'll do it if you want.

Thanks, Chris. I got impatient; see below.

Originally Posted by TheCabinetmaker

...that oil you find under your car with the gasoline leak could be the result of rubberized undercoating being soaked in gasoline...

That's probably our winner. There's a lot of spray-on rubberized undercoating inside there under the tank, and a lot of what is probably dissolved coating that is now a chalky white powder.

Now, the water? Maybe just stuff that's seeping in from up top.

As for "pinhole"? Yeah, um no. Once I got to using a wire brush to clean it up, this is what I found:




Cleaned it up and patched it with a Balkamp/NAPA patch kit. Epoxy (reminds me a lot of JBWeld) reinforced with Fiberglass (I put two layers on it):



We'll see how well it holds...Sent Scott a note for the other tank.

- GA

[Racer Chris]

That should buy you some time at least.
I'm having an event on Sept. 14th.
If Scott's planning to attend maybe you can wait for him to deliver it.

[GregAmy]

Originally Posted by Racer Chris

That should buy you some time at least.
I'm having an event on Sept. 14th.
If Scott's planning to attend maybe you can wait for him to deliver it.

Thanks, Chris. Send me a note with the details on the event regardless and I'll come shame you guys with my "driver"...

- Greg

[Racer Chris]

Originally Posted by GregAmy

Thanks, Chris. Send me a note with the details on the event regardless and I'll come shame you guys with my "driver"...

- Greg

This one's gonna be a fun rally through Marlborough, E. Hampton, Portland, Glastonbury, ending with a BBQ at our (Mary & me) place in Bolton.
I've announced it on the club & world forums already.
Once I update my database with new contacts since last summer I'll be emailing invites soon.
We had a good turnout 2 years ago & I would like to fill my driveway this year.